ALKr (version 0.5.3.1)

classic_ALK: Classic Age-Length Key

Description

classicALK returns an Age-Length Key calculated from a matrix with the count of individuals per age- and length-class, as described by Fridriksson (1934).

Usage

classic_ALK(x, fi = rowSums(x), age_classes = colnames(x), length_classes = rownames(x), name = "", description = "")

Arguments

x

A $i \times j$ matrix with the count of individuals of length $i$ and age $j$.

fi

A vector of length i where fi[i] is the number of fish in the length-class i on the population from which x was sampled. Defaults to the number of samples per length class, which will

age_classes

A vector with the name of each age class. Defaults to the column names of x.

length_classes

A vector with the name of each length class. Defaults to the row names of x.

name

A string with the name of the ALK.

description

A string describing the ALK.

Value

An ALKr object, containing a $i \times j$ matrix with the probability of an individual of length i having age j, i.e. $P(j|i)$, a $i \times j$ matrix with the estimated number of individuals of length i and age j, and information about the method used to generate the key.

References

Fridriksson, A. (1934). On the calculation of age-distribution within a stock of cod by means of relatively few age determinations as a key to measurements on a large scale. Rapp. P.-V. CIEM, 86, 1-5.

Examples

data(hom)
classic_ALK(hom$otoliths[[1]], fi = hom$F1992)